1 /* Exception (throw catch) mechanism, for GDB, the GNU debugger. 2 3 Copyright (C) 1986, 1988, 1989, 1990, 1991, 1992, 1993, 1994, 1995, 1996, 4 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008, 5 2009, 2010 Free Software Foundation, Inc. 6 7 This file is part of GDB. 8 9 This program is free software; you can redistribute it and/or modify 10 it under the terms of the GNU General Public License as published by 11 the Free Software Foundation; either version 3 of the License, or 12 (at your option) any later version. 13 14 This program is distributed in the hope that it will be useful, 15 but WITHOUT ANY WARRANTY; without even the implied warranty of 16 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 17 GNU General Public License for more details. 18 19 You should have received a copy of the GNU General Public License 20 along with this program. If not, see <http://www.gnu.org/licenses/>. */ 21 22 #ifndef EXCEPTIONS_H 23 #define EXCEPTIONS_H 24 25 #include "ui-out.h" 26 #include <setjmp.h> 27 28 /* Reasons for calling throw_exceptions(). NOTE: all reason values 29 must be less than zero. enum value 0 is reserved for internal use 30 as the return value from an initial setjmp(). The function 31 catch_exceptions() reserves values >= 0 as legal results from its 32 wrapped function. */ 33 34 enum return_reason 35 { 36 /* User interrupt. */ 37 RETURN_QUIT = -2, 38 /* Any other error. */ 39 RETURN_ERROR 40 }; 41 42 #define RETURN_MASK(reason) (1 << (int)(-reason)) 43 #define RETURN_MASK_QUIT RETURN_MASK (RETURN_QUIT) 44 #define RETURN_MASK_ERROR RETURN_MASK (RETURN_ERROR) 45 #define RETURN_MASK_ALL (RETURN_MASK_QUIT | RETURN_MASK_ERROR) 46 typedef int return_mask; 47 48 /* Describe all exceptions. */ 49 50 enum errors { 51 GDB_NO_ERROR, 52 /* Any generic error, the corresponding text is in 53 exception.message. */ 54 GENERIC_ERROR, 55 NOT_FOUND_ERROR, 56 57 /* Thread library lacks support necessary for finding thread local 58 storage. */ 59 TLS_NO_LIBRARY_SUPPORT_ERROR, 60 61 /* Load module not found while attempting to find thread local storage. */ 62 TLS_LOAD_MODULE_NOT_FOUND_ERROR, 63 64 /* Thread local storage has not been allocated yet. */ 65 TLS_NOT_ALLOCATED_YET_ERROR, 66 67 /* Something else went wrong while attempting to find thread local 68 storage. The ``struct gdb_exception'' message field provides 69 more detail. */ 70 TLS_GENERIC_ERROR, 71 72 /* Problem parsing an XML document. */ 73 XML_PARSE_ERROR, 74 75 /* Error accessing memory. */ 76 MEMORY_ERROR, 77 78 /* Feature is not supported in this copy of GDB. */ 79 UNSUPPORTED_ERROR, 80 81 /* Add more errors here. */ 82 NR_ERRORS 83 }; 84 85 struct gdb_exception 86 { 87 enum return_reason reason; 88 enum errors error; 89 const char *message; 90 }; 91 92 /* A pre-defined non-exception. */ 93 extern const struct gdb_exception exception_none; 94 95 /* Wrap set/long jmp so that it's more portable (internal to 96 exceptions). */ 97 98 #if defined(HAVE_SIGSETJMP) 99 #define EXCEPTIONS_SIGJMP_BUF sigjmp_buf 100 #define EXCEPTIONS_SIGSETJMP(buf) sigsetjmp((buf), 1) 101 #define EXCEPTIONS_SIGLONGJMP(buf,val) siglongjmp((buf), (val)) 102 #else 103 #define EXCEPTIONS_SIGJMP_BUF jmp_buf 104 #define EXCEPTIONS_SIGSETJMP(buf) setjmp(buf) 105 #define EXCEPTIONS_SIGLONGJMP(buf,val) longjmp((buf), (val)) 106 #endif 107 108 /* Functions to drive the exceptions state m/c (internal to 109 exceptions). */ 110 EXCEPTIONS_SIGJMP_BUF *exceptions_state_mc_init (struct ui_out *func_uiout, 111 volatile struct gdb_exception * 112 exception, 113 return_mask mask); 114 int exceptions_state_mc_action_iter (void); 115 int exceptions_state_mc_action_iter_1 (void); 116 117 /* Macro to wrap up standard try/catch behavior. 118 119 The double loop lets us correctly handle code "break"ing out of the 120 try catch block. (It works as the "break" only exits the inner 121 "while" loop, the outer for loop detects this handling it 122 correctly.) Of course "return" and "goto" are not so lucky. 123 124 For instance: 125 126 *INDENT-OFF* 127 128 volatile struct gdb_exception e; 129 TRY_CATCH (e, RETURN_MASK_ERROR) 130 { 131 } 132 switch (e.reason) 133 { 134 case RETURN_ERROR: ... 135 } 136 137 */ 138 139 #define TRY_CATCH(EXCEPTION,MASK) \ 140 { \ 141 EXCEPTIONS_SIGJMP_BUF *buf = \ 142 exceptions_state_mc_init (uiout, &(EXCEPTION), (MASK)); \ 143 EXCEPTIONS_SIGSETJMP (*buf); \ 144 } \ 145 while (exceptions_state_mc_action_iter ()) \ 146 while (exceptions_state_mc_action_iter_1 ()) 147 148 /* *INDENT-ON* */ 149 150 151 /* If E is an exception, print it's error message on the specified 152 stream. for _fprintf, prefix the message with PREFIX... */ 153 extern void exception_print (struct ui_file *file, struct gdb_exception e); 154 extern void exception_fprintf (struct ui_file *file, struct gdb_exception e, 155 const char *prefix, 156 ...) ATTRIBUTE_PRINTF (3, 4); 157 158 /* Throw an exception (as described by "struct gdb_exception"). Will 159 execute a LONG JUMP to the inner most containing exception handler 160 established using catch_exceptions() (or similar). 161 162 Code normally throws an exception using error() et.al. For various 163 reaons, GDB also contains code that throws an exception directly. 164 For instance, the remote*.c targets contain CNTRL-C signal handlers 165 that propogate the QUIT event up the exception chain. ``This could 166 be a good thing or a dangerous thing.'' -- the Existential 167 Wombat. */ 168 169 extern void throw_exception (struct gdb_exception exception) ATTRIBUTE_NORETURN; 170 extern void throw_verror (enum errors, const char *fmt, va_list ap) 171 ATTRIBUTE_NORETURN ATTRIBUTE_PRINTF (2, 0); 172 extern void throw_vfatal (const char *fmt, va_list ap) 173 ATTRIBUTE_NORETURN ATTRIBUTE_PRINTF (1, 0); 174 extern void throw_error (enum errors error, const char *fmt, ...) 175 ATTRIBUTE_NORETURN ATTRIBUTE_PRINTF (2, 3); 176 177 /* Instead of deprecated_throw_reason, code should use catch_exception 178 and throw_exception. */ 179 extern void deprecated_throw_reason (enum return_reason reason) 180 ATTRIBUTE_NORETURN; 181 182 /* Call FUNC(UIOUT, FUNC_ARGS) but wrapped within an exception 183 handler. If an exception (enum return_reason) is thrown using 184 throw_exception() than all cleanups installed since 185 catch_exceptions() was entered are invoked, the (-ve) exception 186 value is then returned by catch_exceptions. If FUNC() returns 187 normally (with a positive or zero return value) then that value is 188 returned by catch_exceptions(). It is an internal_error() for 189 FUNC() to return a negative value. 190 191 For the period of the FUNC() call: UIOUT is installed as the output 192 builder; ERRSTRING is installed as the error/quit message; and a 193 new cleanup_chain is established. The old values are restored 194 before catch_exceptions() returns. 195 196 The variant catch_exceptions_with_msg() is the same as 197 catch_exceptions() but adds the ability to return an allocated 198 copy of the gdb error message. This is used when a silent error is 199 issued and the caller wants to manually issue the error message. 200 201 MASK specifies what to catch; it is normally set to 202 RETURN_MASK_ALL, if for no other reason than that the code which 203 calls catch_errors might not be set up to deal with a quit which 204 isn't caught. But if the code can deal with it, it generally 205 should be RETURN_MASK_ERROR, unless for some reason it is more 206 useful to abort only the portion of the operation inside the 207 catch_errors. Note that quit should return to the command line 208 fairly quickly, even if some further processing is being done. 209 210 FIXME; cagney/2001-08-13: The need to override the global UIOUT 211 builder variable should just go away. 212 213 This function supersedes catch_errors(). 214 215 This function uses SETJMP() and LONGJUMP(). */ 216 217 struct ui_out; 218 typedef int (catch_exceptions_ftype) (struct ui_out *ui_out, void *args); 219 extern int catch_exceptions (struct ui_out *uiout, 220 catch_exceptions_ftype *func, void *func_args, 221 return_mask mask); 222 typedef void (catch_exception_ftype) (struct ui_out *ui_out, void *args); 223 extern int catch_exceptions_with_msg (struct ui_out *uiout, 224 catch_exceptions_ftype *func, 225 void *func_args, 226 char **gdberrmsg, 227 return_mask mask); 228 229 /* This function, in addition, suppresses the printing of the captured 230 error message. It's up to the client to print it. */ 231 232 extern struct gdb_exception catch_exception (struct ui_out *uiout, 233 catch_exception_ftype *func, 234 void *func_args, 235 return_mask mask); 236 237 /* If CATCH_ERRORS_FTYPE throws an error, catch_errors() returns zero 238 otherwize the result from CATCH_ERRORS_FTYPE is returned. It is 239 probably useful for CATCH_ERRORS_FTYPE to always return a non-zero 240 value. It's unfortunate that, catch_errors() does not return an 241 indication of the exact exception that it caught - quit_flag might 242 help. 243 244 This function is superseded by catch_exceptions(). */ 245 246 typedef int (catch_errors_ftype) (void *); 247 extern int catch_errors (catch_errors_ftype *, void *, char *, return_mask); 248 249 /* Template to catch_errors() that wraps calls to command 250 functions. */ 251 252 typedef void (catch_command_errors_ftype) (char *, int); 253 extern int catch_command_errors (catch_command_errors_ftype *func, char *command, int from_tty, return_mask); 254 255 #endif 256